Field
Apparatuses and methods consistent with the exemplary embodiments relate to an electronic apparatus and a power controlling method thereof, and more particularly to an electronic apparatus and a power controlling method thereof, in which standby power consumption is controlled.
Description of the Related Art
An electronic apparatus including a display apparatus such as a television is provided with a power supply for supplying power needed for operation. The electronic apparatus has a plurality of power modes, and enters a standby mode where voltage being supplied to some components is cut off in order to reduce power consumption if a predetermined time has elapsed without performing any operation.
Although the electronic apparatus enters the standby mode, standby power has to be supplied to a system part so as to perform minimum operation. To this end, the electronic apparatus may include a standby AC/DC converter circuit as a standby-power supply that generates the standby power.
FIG. 1 shows a conventional standby-power supply.
As shown in FIG. 1, a standby-power supply 10 may be achieved by a standby AC/DC converter circuit. Referring to FIG. 1, the conventional standby-power supply 10 operates as follows.
If alternating current (AC) power is applied via a bridge rectifier circuit 11, a pulse width modulation (PWM) integrated circuit (IC) 12 generates a PWM signal. High voltage start-up of the PWM IC 12 makes a switching device Q1 start a switching operation, and voltage VCC makes the PWM IC perform a normal operation, thereby outputting direct current (DC) power as standby power.
Specifically, a pulse voltage generated in the PWM IC 12 is switched by Q1, applied to a secondary side in accordance with a transformation ratio of a transformer 14, and output as a DC voltage to a system part (not shown) for performing the operation of the electronic apparatus via a rectifier D1 and an electrolyte capacitor. The output DC voltage is fed back to a feedback terminal F/B of the PWM IC 12, and thus undergoes regulation based on feedback control of the PWM IC 12.
However, the conventional standby-power supply 10 shown in FIG. 1 always operates in the standby mode of the electronic apparatus, and thus causes loss of power. Also, a circuit itself between the primary and secondary sides of the AC/DC converter 10 causes loss of power transformation regardless of load. That is, standby AC/DC conversion continuously causes loss in the standby mode, and therefore increases the standby power.
Accordingly, in order to decrease the standby power, a gate output of the PWM IC 12 is controlled by the output feedback voltage at the standby mode in such an intermittent manner of switching (e.g., a burst mode or a pulse skip mode,) thereby changing operating times, frequencies, etc. of the switching device Q1.
However, if the burst cycle is extremely lowered (for example, into 1 kHz or lower) so as to decrease the standby power, energy is not normally supplied to the output when an output current is suddenly varied in a section where PWM does not operate, thereby generating a dip of the output voltage, that is, voltage collapse extremely and thus causing a trouble in the system portion.